C11 to c13 copolymers of propene and n-butene



between 100 and 2000 p. s. i. ,peratures in the-rangeof 250450..F. forcontact with the catalyst in chamber 4. The phosphoric acidcatalyst .is preferably used on adsorbent.carriers,.such as kieselguhr, alumina: diatomaceous' earth, or silica,.on which it is precalcined at. about '400500 ZF.

United States Patent C) C11 TO C13.COPOLY-MERS OFPR OPENE'AND n-BUTENE Samuelli. Lippincott and: Howard L. Yowell, West-field, N. J., assignorsto Standard Oil "'Development company, a corporation of Delaware Application June 28, I350, Serial" No. 17 0,748 -3-Claims. .(CL 260-68315) This invention relatesto aprocess for producing watersoluble'type alkyl aromatic sulfonate detergents of high quality with desired economies using. polymers ofmixed propene-butene feeds to obtain the alkyl substituent.

Desired advantages'to be obtained with the present invention are dependent upon the following'fa'ctors:

his not essential to obtain Cizolefinpolymersfrorn pure propene, which isexpensive and of limited availability, forthe alkylation of the aromatic compounds, becausesuitable polymers for thispurpose canbe made from propene-butene mixtures, in'which thepro'pene'is properly proportioned to normal butenes and isobutene.

In polymerizing the. propene-butene mixture,.steps can be. taken to control the reaction and recycling of certain productfractions to obtain improvedvyields of C11 to C13 copolymers .best suited .for alkylating aromatic hydrocarbons, such as, benzene, with least chain fragmentation, more particularly by use of properpolymerization conditions, contact time, and elimination of C7 polymer products from the recycled products.

The alkylation of the aromatic hydrocarbons'with Cu to Crspropenebutene polymers can be carried out satisfactorily and inexpensively with an aluminum chloride sludge catalyst or other activealkylation catalystsat low temperatures with low fragmentation.

'The copolymer alkylated aromatic hydrocarbon jprod- .uct properly fractionated can'be practically lO% sulfonated to yield the desired alkyl aromaticsulfonate prod- .ucts which are substantially as good as thoseobtained from polymers of pure propene in soft waters and 'even surpass them in certain-respects, such as--detergency, in hardiwater.

The process steps involved will be briefly and generally described with referenceto the accompanying fiow diagram and the controlling features will be explained more fully.

The polymerizationstep is carried out with-aphosphoric acid catalyst in a manner similar to'the knowncommercial processes of producing gasoline, but preferably -Wl'th modifications for obtaining high yields of "the desired Cu-C13 olefin polymersto be .used producing the detergents. These desired polymers are chiefly characterizedby high bromine numbers ranging from.88'to 104 and normal boiling points of 360 F.'to- 425 F.

The propene-butene charging stock conta-ining'very The feed containingthe alkenes under:a.pressure .of

v is preheated to tem- The catalyst tends to lose activity by undergoing .complete dehydration, .therefore,.a small amount of water or 'steam is added tothe. charging stock, .e. .g. .tomaintain the activity. The

polymerization reaction .is .oxothermic and 'heat is removed, if necessary from the reaction zoneto' maintain 2 gig?) dle sired reaction tetnperature in' the range of 350- From the. reaction chamber .4,- theresulting product mixture of polymers and unreaeted hydrocarbons is withdrawnrithro'ug'hd'ine 5-10 .21 product recovery =unit comprising a stabilizer 6 in whichzgaseous hydrocarbons, including C2425 unreacted hydrocarbons are separated from the polymers. The polymers condensed to liquid and stabilized are passed by=line "8 to a fractionator 9 for separating by line 10 a CaC-z F.- F.) light fraction, a C1-C8 (-160 F.225 F.) intermediate fraction withdrawn through line 11-, and a Cs+ bottoms fraction. The Cs+ bottoms fraction is passed by line 12 into another fractionator 13, where a C8-C1l (225 F.360 F.) light fraction is removed through line 14, a c i Cis (360 F.425 P.) fraction is removed by line 15-and a-Crs-i- 'heavy fraction is removed byline 16. As will be explainedlater, the fractions of C6-C7 and CsC11 hydrocarbons removed from'fractionators" 9 and. 13 through 10-and14 are best adapted for recycling, as through line 17 to the polymerization reaction Zone 4, the intermediate C1-C8 and Cir-C13'ClliS being removed irom the 'po'lymerization unit as final products. The polymers'maybe'ftactionated under reduced preswre, but thebo'iling points given are'corrected to atmospheric pressure.

While,-in-general, the process of polymerizing the propene-butene feed, as described, is similar to the known processesof polymerizingtheCkCi alkenes to form gasoline or of'polyrnerizing' substantially pure propene to form'Cs, C9, C12 and higher polypropenes, it has now been found that there are certain significant differences when it is desired to obtain detergent alkylates in starting with the polymerization of propene-butene mixtures. For instance, in polymerizing C3-C4 alkene mixtures to produce gasoline and preferabdy anti=knock gasoline, it'is "desirable to have present in the feedas large aproportion of isobutene as possible in order to obtain a large yield of highly-branched CsC12 hydrocarbons. The increased proportion of 'isobutene makes the optimum polymerization temperature relatively lower, of the order dfBGO""F.4001F.,.:and the product which is best to recycle contains the C13+ polymers. In such operations'theprincipal product is made up of 'Csbra'nched olefins, i. e. isooctenes, and triisobutene polymers that boil-below 360 F. If substantially pure propene, with not more than about 1% or 2% butenes present, the optimum polymerization temperature is of the order of 400 F.450''F., thep'r'oduct is largely the C9, propene trimersgin a proportion of about 4050 volume percent oftotal polymer with a minimum of C7 product.

On "the other hand, 'when using the propene-butene feed to obtain particularly the C11C13 polymers (360 F.- 425 F.) :desired for "makingdetergentalkylates, it is -.-advantageous to have present intheolefinfeed'between 22 and 8'.7-mole percentofnormal butenes 6787 tnole percent propene andless than ll-mole percent isobutene. "With this type of feed the 'o'ptimumi'reactiontemperature range is 425 F.-475 F. This kind-of feedforms larger amounts of C7 and C10 olefinsrathenthan-Ca or C9 olefins and in addition fofrtn's substantialamounts of high boiling C11 and low boiling C13 copolymers boiling in the range of 360 F. to-4-2-5 'F.-whieh*can be suit ably used with the C12 olefins'for 'monmalkylatingJaromatics in preparing satisfactory detergent alkylateswh-ile 'keeping the' C7 product within-certain limits. In using :this type of'feed, it was found that advantageously the C7 cut or aCr-Cs fraction .cut should not berecycled but should-be removed from the system to be used for any other'desir'ed purpose, while thecs-a'nd Cs-'Ci1-fcuts can be usefully recycled to improve the desired yields of Gil-C13 olefin polymers. Thus, by eliminating a C1 cut such-as boils in the temperature range of 160 F.- 225". F el-moreparticularlyfrotn'about l'dtl" F. to 210 F from the recycled 'polyme'nimproved' yields of desired TABLE I VOLUME PER CENT POLYMER PRODUCT DISTRIBU- TION IN EQUILIBRIUM Polymerization of C3-C4 alkenes [Phosphoric acid cat. 1,000 p. s. i. g. 0.38 gal./hr./1b./feed rate; 450 1 C C Us 310 ir 13 The above data on the equilibrium mixtures were obtained in the polymerization of feeds containing from between 10 and 3 moles propene per mole of n-butene and show that optimum yields of the desired Cu to C12 polymers are formed in the presence of restricted amounts of C7 polymers, preferably by restricting the proportion of the C1 polymers (boiling in the range of 168 F. to 210 F.) to between 10 and voi. percent.

In controlling the polymerization to obtain maximum yields of ell-C13 copolymers, it has been observed that the C7 copolymers have the tendency of reacting with C3 olefin, propene, to form C10 copolymers, therefore, while elimination of C7 copolymers from any recycled polymer feed aids in lowering this undesired reaction, other controls can also be employed, such as use of optimum reaction temperatures in the range of 425 F. to 475 F. and proper conversion levels, e. g., between about 85% and 95%.

The following tabulated data illustrates a comparison of feeds and their products under exemplary polymerization conditions:

TABLE II Phosphoric acid catalyst polymerization [1,000 p. s. 1. g.; 0.32 gal./hr./lb. feed rate; reaction temp, 450 F.]

I II III Proponen- Propene 33 335? butene-isofeed, mole feed, mole f bltene percen ee 111 1 percent percent Feed compositions:

40. 6 31. 3 21. 3 58.8 59.6 5.7 0. 4 46. 2 8.1 17. 3 Isobutenes 0. 0 3, 9 0 6. 6 0. 5 0. 6 Olefin conversion, weight percent based on olofins:

Propane 88 96 98 n-butenes 94 36 Isobnfpna 97 Total oleiins 88 95 93 Polymer yield 86 93 90 Selectivity 98 98 97 Polymer products, volume percen Cfi(LB.P-168 F.) 5.9 7.7 4.3 0 (168-210 1 4.6 17.9 2 7 (ls-Cu (210 F.375 F.) 73.8 56.6 55,4 On (375415 F.) 12.9 11. 4 7, 9 C13 (415 F.+) 2.8 6.4 4.0

The foregoing data shows how a substantially butenefree propene feed I tends to produce very little C1 polymer while the mixed feed III containing substantial amounts of isobutene produces excessively large amounts of C7 polymers and relatively little C12 or C11-C13 poly mers. The polymer product from the propene feed I substantially free of n-butene on being distilled shows more pronounced distillation plateaus for the C6, C9, and C12 polymers; and although it has a larger percentage of precisely C12 polymers, it has a lower total suitable C11-C13 polymer cut (360 F.425 F.) than the polymer product of the propene-n-butene feed II. In using the C12 polymers from each of the products for alkylating benzene and sulfonating the resulting alkyiate, it was noticed that the final products obtained from the C12 polymers of the mixed propene-n-butene feed contained less unsulfonated oil in the sulfonated product, of the order of 1.2 weight percent, as compared to about 2 weight percent from the pure propene feed and 1.8 weight percent from the feed containing substantial amounts of isobutene.

The Oil-C13 polymers of the propene-n-butene feed may be used to mono-alkylate aromatic compounds, such as benzene or toluene, naphthalene, and other aromatic hydrocarbons, to known methods, employing H2804, BFa, anhydrous HP, or AlCl3.CHCl3 complex as catalysts, but the preferred alkylation process uses an aluminum chloride complex catalyst which is a viscous liquid nearly insoluble in the hydrocarbon products, thus making it easy to separate, to handle and avoid corrosion difiiculties. The aluminum chloride complex catalyst is typically composed of about 38-42 weight percent aluminum chloride combined with olefin polymers and the aromatic hydrocarbons with only about 1% free aluminum chloride present when the catalyst is active. As the catalyst becomes spent, its content of aluminum chloride becomes diminished. The spent catalyst is readily reactivated by admixing fresh aluminum chloride.

To carry out the alkylation, the C11C13 polymers are first dried in any suitable manner, for example, by mixing with the aromatic hydrocarbon reactant and distilling the water azeotropically or by treatment with a chemical drier, such as calcium chloride or alumina.

As shown in the drawing, the polymer feed from the fractionator 13 is delivered by line 15 to the fractionating or drying column 18, where, mixed with the aromatic compound, the water is removed overhead by line 19; and the dried reactant feed mixture is passed by line 20 and pump 21 for discharge through jets 22 at the bottom of the alkylation reactor 23. With an excess molar proportion of the aromatic reactant present the olefin reactant substantially instantaneously reacts on coming into contact with the active complex catalyst which settles as a liquid mass at the bottom of the reactor 23. The alkylated product formed together with unreacted aromatic reactant passes upwardly above the liquid catalyst level 24 and is withdrawn through line 25. Any desired proportion of this withdrawn product can be recycled through line 26 for supplying part of the aromatic reactant required. A remaining portion of the polymer product is led by line 27 into a settler 28 for removing any small amount of the catalyst entrained, such separated catalyst is removed from separator 28 by line 29 either to be discarded through line 30 as spent catalyst or be passed by line 31 into a catalyst make-up tank 32 where fresh aluminum chloride is admixed from hopper 33. Catalyst can be withdrawn from any part of reactor 23, e. g. by line 34 to be discarded through line 30 or to be passed into tank 32 by line 31 or to be recycled through line 38.

The general operation conditions for the alkylation reaction are: temperatures of 35 F. to F.; an aromatic reactant to olefin reactant volume ratio of at least 2:1 and preferably about 5:1 or higher; a contact time of about 10 to 30 minutes; a catalyst sludge to hydrocarbon ratio in the reactor of about 0.1 to 1.0. Each of these conditions can be varied to beyond the limits mentioned but any large variation may tend to be adverse. For example, the highest yields of detergent alkylate are obtained at the lower reaction temperatures, the yield increasing from 80 to 91 volume percent in lowering the temperature from 115 F. to 40 F. due to the formation of less degradation products. At above 115 F., undesired fractionation reactions tend to occur. At below 35 F. there is a tendency for the aromatic reactant, e. g. benzene to become crystalline. The alkylation reaction is substantially instantaneous; therefore, the resideuce time of the reactants in contact with -'the catalyst can'be as short as-practical. Increasing thecontact time tends tolowerthe yieldof thedesired alkylate. There are advantages tobe gained-by having the catalyst sludge to--hydrocarbon ratio as low as possible 'for decreasing contact time'and reducing cost of catalyst. The recycled product stream can vary from practically pure-hydrocarbon (alkylate unreacted aromatic hydrocarbon) to 50% sludge, but it is advantageous to recycle the hydrocarbon product with verylittle sludge. The-recycled aromatic -reactant does. not accumulate impurities to an appreciable-extent. Typical-plant operation data is-set forth in the iollowing-tablez 'TABLEfIII Summarized pilot plant data conditions:

Reactor temperatures, F 41 Aromatic-olefin volume ratio 5 Hydrocarbon feed, liters/hr 3.95 AlC l3 addition gL/hr 25 HCI, addition, weight percent on AlCls 27 Water, weight percent on AlCl3 0.2 ,Recycledrate, liters/hr 190 Sludge-hydrocarbon ratio 0.39

Total alkylate:

t-Degra ati np od c vol-percent 11 Detergent alkylate, vol, percent 73 Polymer and heavy alkylate, vol. percent 16 Yields based. on olefin feed, vol. percent: r

.Total. alkylate 125 Detergent alkylate 91 Sludge product 12 'Using similar conditions in alkylating toluene with a propene-butene Cir-C13 copolymer but using ll5'F..reaction temperature a yield of 84% detergent alkylate was obtained. The-pressures maintained in the reactionzone aremoderate, e. g. 5 to p.-s. i. g.

The hydrocarbon-product is withdrawn from the separator 28 by line '38to a chemical treating-unit 39 for removal-of any entrained catalyst or acid, e. g. HCl. For-this treatment caustic washing followed by water ,washing may be used or filtering through adsorbents such -as bauxite or-clay to obtain a neutral hydrocarbon product ofclose to zero brominenumber.

*The purified hydrocarbon product is passed by line- 40 into a fractionator 41 for stripping out'the unreacted aromatic compound, which taken overhead by line 42 can-be-mixed with the polymer to form fresh feed. The alkylate-product is'passed by line 43 into another fractionator 44 to strip out the light alkylate (degradation :product) -boiling-below-5 18 P. as overhead product removedby-line- 45. The desired alkylate-fraction boiling in therange of 518 F.680 F. is separated as an in- .termediattraction such as a side stream removedby line 46. Tho residual heavy alkylate is removed as ottoms 7 by line-47.

Thefinishing-treatment of the alkylate for obtaining the, sulfonate detergents is of no particular concern to the present invention, since the alkylate obtained'with-the use of the aluminum chloride complex catalyst is not contaminated with excessive amounts of unsulfonatable materials andis readily sulfonated to practically 100% using conventional sulfonation methods. The presence of -mor'e-than about 1.5% unsulfonatable material, such-as polymer tends to make the alky-late unstable with respect to'color-and forms unsaponifiable material which lowers the quality of the detergents produced. The alkylate may 'besubjected to chemical treatments such as bleaching with sodium hypochlorite or washing with sulfuric acid andv passing over activated clays to remove unsaturated com- ;pounds but it is preferred to minimize the chemical treatment-of the alkylate on account of the cost and losses of alleylate material. The finishing treatment and sulfo- -na-tion is-indicated to be conducted in unit 48. The sulfonation of the alkylates may be carried out with a "variety of acid strengths, e. g. from 100% H2804 to oleum-.containing 20% S03 and-liquid $03. The sulfo- --nation-' temperature is' higher for the weaker acids. Using -20% oleumvin the amount-of 1.4timesthe-we'ght of .tions using a precise C12 alkylate, the alkylate is stirred-with the acid for a period of about 10 minutes while the temperature of the mixture is maintained=--below-'77 F. Thereafter thetemperature of the reaction product canbe increased to 131 -F.,-and then the reaction mixture can be quenched by addition of-cold .waterandi 30% sodium hydroxide solution, keeping/the temperature .below;140 F. Sufii'cient sodium sulfate is added-toabring 'the concentrate of the active ingredient. to. 40-% -,by.. weight .and. the..mixture..is...dried.in a-stainless steelv drum. drier using 60 lb..steam pressure or is spray ,dried. This is ,a" standardized procedure when onlya traceofhydrocarbon-materialremainswin the finished product. If the product contains a substantial amount of unsulfonatedloil it. has. tobesllbj cte to a deoiling,- such as by means -of--extraction orchemical treatment prior to the drying.

Using the described standardized procedure ;of sulfonating and recovering the finished detergents, analyses, and detergency evaluationstwere madeonacompara'tive basis to .find the effect of. the n-butenes inuthevcopolymer alkylate with reference to analkylate formed from-.a-s'ubstantial pure propylene polymer. Each. of the olefin feeds subjected to phosphoric catalyst polymerization inv the manner containeda traceof less than. 1% isobutene and -.usual amounts of-inert paraflins; therefore,qthe. feedrcomposition isv given on the .basis of total: olefins. The. comparable-data is summarized in. the following .table.

TABLE IV Tests 1 1 v2 3 Feed to polymerization unit:

Percent propene 98 '91 80 Percent. n-butene 2 9 20 (On total olefin basis). Sultanate yield, mole percent on alkylate 100 100 ,100 Unsolfunated oil, weight; percent on alkylate .1 2. 6 1.9 l 2 Color of dry powder Launderometer evaluations:

Soil removal 0.5 Weight percent in distilled water 80 '70 I 0.5 weight percent in 120 p. p. m. hard water. 105 Y 125 0.5 weight percent in 360 p. p.-m. hard water, 80 z .100

Soil removal relative to a commercially available sodium alkyl sulfate detergent at 0.5% in .p. p. in. hard water as .100.

1 Near-white.

' similar full suds formation and stability.

.For the purpose of the IV each. of the polymers, derivatives thereof, were comparison shown in Table the alkylate, and the sulfonate formed under the sametcondipolymer cut boilingv .fIfQH'l 375 Fm415 'F. for'the alkylation of benzeneand a precise C12 .alkylate cut boiling in the range of On this basis the .Polymers of substantially purepropylene tend to give a substantially higher ;yield of detergent alkylate regardless of the-kind of alkylation catalyst used, for example either'hydrogen fluoride or aluminum chloride. This is so mainly because the C12 polymers of propylene more selectively form the C12 .alk-ylate, .whereas the copolymers of propenebutenes, even boiling in the same range, tendto yield some C11 and C13 alkyl benzene. Hence, studies were undertaken tofind out if the C11 and C13 alkyl'benzene from the copolymers could be-used to obtain sulfonate detergents of as high quality as the Ciz'alkyl benzene sul- "fonate, thus permitting a wider alkylate cut to be used and 1 On total oletins.

The above table indicates the variation in ranges of the bromine numbers and of the molecular weights of the polymers, thus showing that the C11-C13 olefins are present in the wider cuts of the propene-butene copolyrners. Using the wider alkylate fractions formed from the copolyrners the yields were substantially the same as obtained from the tetrapropylene polymers, thus showlng that theCu-Cn copolyrners did not undergo any substantially larger amount of fragmentation than the tetrapropylene polymers during the alkylation under suitable alkylation conditions. The sulfonation of the alkylates formed from the Cir-C13 copolyrners was practically The alkylate products from each type of polymer and copolymer were fractionated and separately sulfonated in order to compare the detersive quality of the resulting sulfonates in both soft and hard waters. These fundamental detergency studies clearly demonstrate that 1n comparing the C11 with C13 and C12 alkyl aromatic sulfonates, the detergency of the sodium salts increases with increased molecular weight when tested in distilled water, but decreases with increasing molecular weight when tested in hard water, that is, when each particular sulfonate is tested alone. However, it was noted that there is a synergistic effect when the various sulfonates are blended which appears to be related to the wetting power of the sulfonate in combination with the detersive power, that is a function of the number and size of micelles in solution. Thus, while a shorter alkyl chain, e. g. C11 decreases the tendency for the molecule to coalesce into micelles and the longer alkyl chain, e. g., C13, decreases wetting power, each of these effects can be counterbalanced by a mixture of the sulfonateswlth shorter and longer alkyl chains. Another factor is the location of the benzene or aromatic ring on the alkyl chain and the degree of branching of the alkyl cham. As the ring is moved toward the center of the alkyl chain and as the alkyl chain is lengthened there is a lowering in surface tension of water; however, branching of the chain onhances the wetting power. These fundamental studies are believed to explain to some extent how the overall effects obtained with the sulfonates of wider boiling alkylates from the propene-butene copolymer detergents which were practically equal to the sulfonates from tetrapropylene (C12) alkylates in soft water and are substantially better in hard waters. Comparable data are shown in the following table:

TABLE VI Launderometer evaluations of sulfonates from various alkylates AL TESTS WITH 0.5 WEIGHT PERCENT CON- SOIL REMOV CENTRATION Relative soil removal Type of water used Nature of detergent alkylate Distilled 240 p. p. 111. water hard water 0 ol ropene alkylate 45 1 C: Enga e-propene alkylate 1ins) 0 -0 butene-propene alkylate Soil removal relative to a commercially available sodium alkyl sulfate detergent at 0.5% in 240 p. p. m. hard water as 100.

The data of Table VI illustrate how the alkylates formed from the copolyrners of butene and propene tend to have higher detersive power in hard waters. This data is representative of results obtained from alkylates formed of propene-butene copolyrners containing 3 to 10 moles of propene per mole of butene. The data also indicates the desirable synergistic effect obtained in having C11 and C13 copolyrners present.

To summarize the principal features of this invention:

(1) It is advantageous to form the alkylating olefin polymers by copolymerizing propene with butene, preferably having 3 to 10 moles of propene per mole of normal butene and less than /2 mole isobutene present in the olefin feed.

(2) It is advantageous to enhance the yields of C11C13 copolyrners from the propene-butene feeds by recycling the C6 and Ca-Cn polymers with a C1 polymer cut eliminated.

(3) In alkylating the aromatics with the coplymers of the propene-butene feeds, it is advantageous to use as the alkylate product for sulfonation a wide boiling fraction containing the C11-C13 alkyl aromatics having an initial boiling point in the range of 518 F.530 F. and a final end point in the range of 630 F.-680 F. in order to obtain maximum yields of suitable sulfonate detergents of both high wetting and detersive power in soft and hard waters.

What is claimed is:

1. In a process for preparing C11 to C1 copolymers of propene and n-butene suitable as alkylating reactants for producing alkyl aromatic sulfonate detergents, the improvement which comprises copolymerizing an olefin mixture of propene and butenes containing principally propene and normal butene in a proportion of 3 to 10 moles of propene per mole of n-butene and less than /2 mole of isobutene per mole of n-butene in the presence of a phosphoric acid polymerization catalyst under polymerization conditions at 350 F. to 500 F., maintaining a polymer conversion yield of said olefin mixture at to weight per cent and preventing recycling of C7 copolymers to hold the proportion of resulting C1 copolymers formed in the resulting reaction mixture product within the range of 10 to 20 volume per cent of the total polymer product, and separating from the total polymer product a C11 to C13 copolymer fraction boiling in the range of 360 F. to 425 F. for use as alkylating reactants.

2. In a process for preparing C11-C13 copolyrners of propene and n-butene suitable for use as alkylating reactants in preparing alkyl aromatic sulfonate detergents, the improvement which comprises copolymerizing 3 to 10 moles of propene with one mole of n-butene in a mixture thereof containing less than /2 mole of isobuteue per mole of n-butene in the presence of a phosphoric acid catalyst under polymerization reaction conditions at temperatures in the range of 350 F. to 500 F., maintaining a polymer conversion yield of said olefin mixture at 85 to 95 weight per cent and preventing recycling of C1 C0- polymers to hold resulting C7 copolyrners formed in the resulting reaction mixture product within the range of 10 to 20 volume per cent of total polymer product, separating from said polymer product a C7 copolymer rich fraction boiling in the range of 160 F. to 225 F. and C11 to C13 copolyrners boiling in the range of 360 F. to 425 F., and recycling remaining polymer product boiling below 360 F. from which said O: copolymerrich fraction is eliminated.

3. In a process for producing C11 to C13 copolymers of propene and n-butene suitable for use as alkylating reactants to prepare alkyl aromatic sulfonate detergents, the improvement which comprises continuously feeding an olefin feed containing 67 to 87 mole per cent propene, between 22 and 8.7 mole per cent n-butene and less than 11 mole per cent isobutene under a pressure of to 2000 p. s. i. g. into contact with a phosphoric acid polymerization catalyst in a polymerization reaction zone, maintaining a reaction temperature in the range of 425 F. to 475 F. in said reaction Zone, continuously withdrawing from the reaction zone a resulting polymerization product containing between 10 and 20 volume per cent of C7 copolyrners, separating from the withdrawn polymerization reaction product 01 copolyrners boiling in the range of 168 F. to 210 F. and C11 to C13 copolyrners -35 boiling in the range of 360 F. to 425 F., recycling remaining polymeriaztion reacti fm zlroguctg Eomprisling Cs OTHER REFERENCES and C8 to C 11 olefin polymers ree o sai 7 copo ymers to said reaction zone in maiitaining reaction of 3 to 10 5 32?? and Chem" pages 1067 1069 moles of propene With 1 mole of n-butene therein.

5 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,232,118 Kyrides Feb. 18, 1941 10 2,517,720 Schaad Aug. 8, 1950 

1. IN A PROCESS FOR PREPARING C11 TO C13 COPOLYMERS OF PROPENE AND N-BUTENE SUITABLE AS ALKYLATING REACTANTS FOR PRODUCING ALKYL AROMATIC SULFONATE DETERGENTS, THE IMPROVEMENT WHICH COMPRISES COPOLYMERIZING AN OLEFIN MIXTURE OF PROPENE AND BUTENES CONTAINING PRINCIPALLY PROPENE AND NORMAL BUTENE IN A PROPORTION OF 3 TO 10 MOLES OF PROPENE PER MOLE OF N-BUTENE AND LESS THAN 1/2 MOLE OF ISOBUTENE PER MOLE OF N-BUTENE IN THE PRESENCE OF A PHOSPHORIC ACID POLYMERIZATION CATALYST UNDER POLYMERIZATION CONDITIONS AT 350* F. TO 500* F., MAINTAINING A POLYMER CONVERSION YIELD OF SAID OLEFIN MIXTURE AT 85 TO 95 WEIGHT PER CENT AND PREVENTING RECYCLING OF C7 COPOLYMERS TO HOLD THE PROPORTION OF RESULTING C7 COPOLYMERS FORMED IN THE RESULTING REACTION MIXTURE PRODUCT WITHIN THE RANGE OF 10 TO 20 VOLUME PER CENT OF THE TOTAL POLYMER PRODUCT, AND SEPARATING FROM THE TOTAL POLYMER PRODUCT A C11 TO C12 COPOLYMER FRACTION BOILING IN THE RANGE OF 360* F. TO 425* F. FOR USE AS ALKYLATING REACTANTS. 